Balanced activation force and bistable valve system and method

ABSTRACT

Some embodiments include a valve assembly with a metering seal including a main channel including regions with a first diameter and regions with a second diameter, where the first diameter is smaller than the second diameter. Some embodiments include a stem positioned in the metering seal extending from at least a first end of the metering seal to a second end of the metering seal. In some embodiments, the stem has a fluted section positioned between two non-fluted sections, where the diameter of stem in the fluted section is smaller than the diameter of the stem in the non-fluted sections. Some embodiments include a first and second flow channel extending across at least a partial width of the metering seal, where the first flow channel is positioned at the first end of the metering seal, and the second flow channel is positioned at the second end of the metering seal.

RELATED APPLICATIONS

This application claims priority to U.S. provisional application Ser.No. 62/567,734, filed on Oct. 3, 2017, the entire contents of which areincorporated herein by reference.

BACKGROUND

Conventional valves generally require biasing devices to provide digitalon and off control while providing low activation energy independent ofinlet pressures with bistable on/off functions.

SUMMARY OF THE INVENTION

A valve assembly comprising a metering seal comprising a main channel,the main channel including regions with a first diameter and regionswith at least a second diameter, where the first diameter is smallerthan the second diameter. Some embodiments include a stem positioned inthe metering seal extending from at least a first end of the meteringseal to a second end of the metering seal. In some embodiments, the stemcomprises a fluted section positioned between two non-fluted sections,where the diameter of stem in the fluted section is smaller than thediameter of the stem in the non-fluted sections. Some embodimentsinclude a first and second flow channel extending across at least apartial width of the metering seal, where the first flow channel ispositioned at the first end of the metering seal, and the second flowchannel is positioned at the second end of the metering seal.

Some embodiments include a first flow channel extending to and couplingwith the main channel. In some embodiments, the second flow channelextend to and couples with the main channel. Some embodiments comprise alower flow channel extending to and coupled to the first flow channel.Some embodiments further comprise an upper flow channel extending to andcoupled to the second flow channel.

In some embodiments, the lower flow channel extends from at least one ofa fluid supply and an actuable valve, where the actuable valve isconfigured to at least partially open and close to control passage offluid to the lower flow channel.

In some embodiments, the upper flow channel extends from at least one ofa fluid supply and an actuable valve, where the actuable valve isconfigured to at least partially open and close to control passage offluid to the upper flow channel. In some embodiments, at least a portionof one or more of the non-fluted sections comprises a diameterdimensioned to couple with the metering seal in the main channel inregions that comprise the second diameter.

Some embodiments include at least a partial seal or fluid-tight sealthat is formed by the coupling of the one or more of the non-flutedsections coupling with the metering seal in the main channel in regionsthat comprise the second diameter.

In some embodiments, the stem is positioned in the main channel so thatat least a portion of the fluted section is coupled with or proximate aregion of the main channel comprising the second diameter. In someembodiments, the stem is positioned in the main channel as anarrangement with at least a portion of the fluted section being at leastone of coupled with, proximate to, and fluidly coupled to the secondflow channel, the arrangement configured to enable fluid flow betweenthe main channel and the second flow channel.

In some embodiments, the stem is positioned in the main channel as anarrangement with at least a portion of the non-fluted section being atleast one of coupled with, and proximate to the second flow channel,where the arrangement is configured to at least partially prevent fluidflow between the main channel and the second flow channel.

In some embodiments, the stem is positioned in the main channel as anarrangement with at least a portion of the fluted section being at leastone of coupled with, proximate to, and fluidly coupled to the secondflow channel, where the arrangement is configured to enable fluid flowout of the main channel adjacent the second end of the metering seal.

Some embodiments comprise at least one gap between the inner surface ofmetering seal and the outer surface of the stem, where the gap isconfigured and arranged to enable fluid to communicate from a lowerchamber of an adjacent valve to an upper chamber of an adjacent valve tobring the pressure in the upper chamber up to the pressure in the lowerchamber.

In some embodiments, the stem comprises a bistable state held in aposition in the main channel by friction between one or more of thenon-fluted sections and an internal surface of the main channelcomprising the first diameter. In some embodiments, the position of thestem enables a fluid coupling of the first and second flow channels andthe main channel.

Some embodiments include an assembly comprising a valve assemblycomprising a flow control side and a metering side, where the flowcontrol side comprises valve separating a lower chamber and an upperchamber, and the valve is configured and arranged to control fluid flowbetween the flow control side and the metering side. In someembodiments, the metering side comprises a metering seal comprising amain channel, where the main channel includes regions with a firstdiameter and regions with at least a second diameter, and where thefirst diameter is smaller than the second diameter.

Some embodiments include a stem positioned in the metering sealextending from at least a first end of the metering seal to a second endof the metering seal, where the stem comprises a fluted sectionpositioned between two non-fluted sections, and where the diameter ofstem in the fluted section is smaller than the diameter of the stem inthe non-fluted sections.

In some embodiments, the first and second flow channels extending acrossat least a partial width of the metering seal, and the first flowchannel is positioned at the first end of the metering seal, and thesecond flow channel positioned at the second end of the metering seal.

Some embodiments comprise a lower flow channel extending to and coupledto the first flow channel, and an upper flow channel extending to andcoupled to the second flow channel, where the first and second flowchannels extend to and couple with the main channel.

Some embodiments comprise a lower flow channel extending between theflow control side and the metering side and coupled to the first flowchannel, and an upper flow channel extending between the flow controlside and the metering side and coupled to the second flow channel.

Some embodiments comprise at least one gap between the inner surface ofmetering seal and the outer surface of the stem, where the gap isconfigured and arranged to enable fluid to communicate between the lowerchamber and the upper chamber via the metering seal.

Some embodiments include a valve stem control method comprisingproviding at least one metering seal and stem assembly, where the atleast one metering seal and stem assembly comprising a plurality ofsealing zones. Some embodiments provide a balanced fluidic pressure tothe at least one metering seal and stem assembly, where the fluidicpressure is substantially balanced to substantially cancel a forceacting and/or inducing momentum of at least a portion of the stemassembly.

In some embodiments, the plurality of sealing zones comprises threesealing zones of the at least one metering seal. In some embodiments,the plurality of sealing zones enables at least one of an on function orposition of a valve and an off function or position of a valve. In someembodiments, the stem comprises a bistable condition when exposed to twoequal and opposite fluid forces at the on and off functions orpositions, where the bistable condition enables a digital selection ofthe on function or position of a valve and/or the off function orposition of a valve.

Some embodiments include an on function or position, the plurality ofsealing zones comprises a middle zone with two zones at each end, thetwo zones being exposed to atmospheric pressure, wherein a seal of themiddle zone is closed, and an upper seal zone of the two zones is openedto depressurize. In some embodiments, with an off function or position,the stem is moved so that a middle zone of the plurality of zones isopen and the two zones are sealed closed.

Some embodiments include a fluid control method comprising providing afluted stem positioned in a metering seal, where the fluted stem ispositioned in the metering seal to substantially cancel two equal andopposite fluid forces fluid forces acting on generally opposite ends ofthe metering stem. Further, by positioning and dimensioning the stem toform a fluidically sealed middle zone enabling a digital selection ofthe on function or position and/or the off function or position of thevalve. In some embodiments, the bistable on/off condition is producedsolely as a result of the two equal and opposite fluid forces.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of a valve assembly in accordance withsome embodiments of the invention.

FIG. 2 shows a cross-section of the valve assembly of FIG. 1 in a closedposition according to one embodiment of the invention.

FIG. 3A depicts an enlarged cross-sectional view of a portion of thevalve assembly of FIG. 1 according to some embodiments of the invention.

FIG. 3B illustrates a metering seal of the valve assembly of FIG. 1 inaccordance with some embodiments of the invention.

FIG. 3C illustrates a stem of the metering seal of FIG. 3B of the valveassembly of FIG. 1 in accordance with some embodiments of the invention.

FIG. 3D illustrates a partial cross-section of a portion of the meteringseal with stem of FIG. 3A in accordance with some embodiments of theinvention.

FIG. 4 shows a cross-section of a valve in an open position according toone embodiment of the invention

FIG. 5A depicts an enlarged view of a portion of the valve of FIG. 4according to some embodiments of the invention.

FIG. 5B illustrates a partial cross-section of a portion of the meteringseal with stem of FIG. 5A in accordance with some embodiments of theinvention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways. Also, it is to be understood thatthe phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having” and variations thereof herein ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items. Unless specified or limited otherwise, theterms “mounted,” “connected,” “supported,” and “coupled” and variationsthereof are used broadly and encompass both direct and indirectmountings, connections, supports, and couplings. Further, “connected”and “coupled” are not restricted to physical or mechanical connectionsor couplings.

The following discussion is presented to enable a person skilled in theart to make and use embodiments of the invention. Various modificationsto the illustrated embodiments will be readily apparent to those skilledin the art, and the generic principles herein can be applied to otherembodiments and applications without departing from embodiments of theinvention. Thus, embodiments of the invention are not intended to belimited to embodiments shown, but are to be accorded the widest scopeconsistent with the principles and features disclosed herein. Thefollowing detailed description is to be read with reference to thefigures, in which like elements in different figures have like referencenumerals. The figures, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope ofembodiments of the invention. Skilled artisans will recognize theexamples provided herein have many useful alternatives and fall withinthe scope of embodiments of the invention.

Some embodiments of the invention provide a valve capable of relativelyhigh flow rates at relatively low pressures. Some embodiments provide avalve capable of bistable on/off conditions without relying on biasdevices, which simplifies the mechanism. Further, some embodimentsinclude a low activation valve which is substantially independent ofinlet pressures. For example, FIG. 1 shows a perspective view of a valveassembly 100 in accordance with some embodiments of the invention. Insome embodiments, the valve assembly 100 comprises a valve cap 105including at least one aperture 107. Further, in some embodiments, thevalve assembly 100 can comprise a coupled valve body 130 including afluid inlet 135. In some embodiments, the valve assembly 100 cancomprise a fluid outlet body 115 including a fluid outlet 117. Someembodiments include structure couplings or elements 125, 127 adjacent orcoupled to a housing 140 at least partially enclosing a metering seal177 (shown in FIGS. 2, 3A-3D, 4, and 5A-5B).

FIG. 2 shows a cross-section of the valve assembly 100 of FIG. 1 in aclosed position according to one embodiment of the invention. FIG. 3depicts an enlarged cross-sectional view of a portion of the valveassembly 100 of FIG. 1 according to some embodiments of the invention.As illustrated, some embodiments include a valve assembly architecturethat is divided into two different sides, the flow control side (shownas 175 a), and the metering side (shown as 175 b). In some embodiments,at least a portion of the valve assembly architecture of the valveassembly 100, including the flow control side 175 a, and/or the meteringside 175 b can be coupled or integrated into the valve assembly 100 tocontrol one or more functions of the valve assembly 100 (e.g., such asturning a valve of the valve assembly on and off).

Referring to FIG. 2, in some embodiments of the invention, the flowcontrol side 175 a can include a valve 162 with flexible diaphragm 160with its upper chamber A2 (marked as 180 b) and lower chamber A1 (markedas 180 a) (see FIG. 1). In some embodiments, the upper chamber 180 b cancomprise a larger area than the lower chamber 180 a. In this instance,when it is pressurized to a pressure equal to the inlet pressure of thelower chamber 180 a, the net force on the diaphragm 160 can push thediaphragm 160 down to a closed position.

In some embodiments, the both upper chamber 180 b and lower chamber 180a can be in fluid communication with the metering side 175 b. Forexample, in some embodiments, both the upper chamber 180 b and lowerchamber 180 a are in communication with the metering side 175 b throughfluid channels. In some embodiments of the invention, the metering side175 b can comprise two main components, a stem 129 with different zonesand flutes corresponding to three different sealing zones, zone 200,zone 225, and zone 250 of the metering seal 175 b. In some embodiments,the lower chamber 180 a can be coupled to the metering side 175 b at alocation between the sealing zone 225 and zone 250 via a flow channel(180 a). In some embodiments, the upper chamber 180 b can be coupled tothe metering side 175 b at the location between the sealing zone 225 andzone 200 via another flow channel (upper flow channel 150).

In some embodiments of the invention, a moveable stem 129 can bepositioned within the metering seal 177, with the stem 129 extendingbetween at least a first end 177 a of the metering seal 177 and thesecond end 177 b of the metering seal 177. In some embodiments of theinvention, the moveable stem 129 can be moved within the metering seal177 (i.e., back and forth between at least the first end 177 a andsecond end 177 b of the metering seal 177) to provide control over fluidflow between the flow control side 175 a and the metering side 175 b.FIGS. 3B and 3C provide more details of structure of the moveable stem129 and metering seal 177. For example, FIG. 3B illustrates a meteringseal 177 of the valve assembly 100 of FIG. 1 in accordance with someembodiments of the invention, and FIG. 3C illustrates a stem 129 of themetering seal 177 of FIG. 3B of the valve assembly 100 of FIG. 1 inaccordance with some embodiments of the invention. Referring to themetering seal 177 of FIG. 3B, in some embodiments, the metering seal 177can comprise a main channel 178 into which the stem 129 of FIG. 3C canreside or be inserted. In some embodiments, the main channel 178 canvary in diameter through at least a partial length of the metering seal177, where in some regions, the diameter is approximate to the diameterof at least a portion of the metering seal 177 so that an at leastpartial fluid seal or fluid-tight seal can be formed while the stem 129remains moveable within the metering seal 177. Thus, in someembodiments, the diameter of the main channel 178 and the maximumdiameter of any portion of the stem 129 are not so close that the stem129 cannot be inserted into the metering seal 177, and the stem 129 doesnot become immobile in the metering seal 177 or the main channel 178 ofthe metering seal 177. For example, in one non-limiting embodiment, themetering seal 177 can comprise regions 180, 182, 184 where the diameterof the main channel 178 is narrower than regions 186, 188.

In some embodiments, the diameter (i.e., a first diameter) of the mainchannel 178 within at least a portion of regions of any two or more ofthe regions 180, 182, 184 can be the same or substantially the same.Further, the diameter (i.e., a second diameter) of the main channel 178within at least a portion of regions of the regions 186, 188 can be thesame or substantially the same. Further, as illustrated, the firstdiameter (of the channel 178) is smaller than the second diameter (ofthe channel 178).

Further, in some embodiments, the metering seal 177 can comprisechannels that extend across at least a partial length of a diameter ofthe metering seal 177. For example, some embodiments include a firstchannel 188 a at a first end 177 a of the metering seal 177 (i.e., inthe region of the zone 250). Further, some embodiments include a secondchannel 188 b at a second end 177 b of the metering seal 177 (i.e., inthe region of the zone 200). In some embodiments, either one or both ofthe first and second channels 188 a, 188 b can extend to and fluidlycouple with the main channel 178 of the metering seal 177.

Turning to FIG. 3C, the stem 129 can comprise a fluted section 129 abetween sections 129 b, 129 c extending to or proximate each end of thestem 129. For example, the section 129 c can extend from one end of thefluted section 129 a towards the first end 190 a of the stem 129, andthe section 129 b can extend from the opposite end of the fluted section129 a towards a second end 190 b of the stem 129. In this instance, oneor more of the sections 129 b, 129 c can comprise a diameter such that apartial fluid seal or fluid-tight seal can be formed with one or more ofthe narrower regions 180, 182, 184 of the metering seal. For example, insome embodiments, the stem 129 can be moved down in the main channel 178(i.e. towards the end of the valve assembly 100 with fluid outlet body115) so that a sealing zone on the stem 129 comprising the section 129 bcan form a partial fluid seal or fluid-tight seal with region 180 of themetering seal 177 at the sealing zone 200 of the metering seal 177 toprevent fluid from bleeding to atmosphere and concurrently. In thisinstance, the flutes section of the stem (129 a) is at the sealing zone225 of the metering seal 177 where the fluted section 129 a ispositioned within the region 182 of the metering seal 177, providing agap that can allow fluid to communicate from the lower chamber 180 a tothe upper chamber 180 b (via lower flow channel 155 and upper flowchannel 150). This structure is represented in FIG. 3A, and in thisinstance, allows the valve assembly 100 to bring the pressure in theupper chamber 180 b up to the pressure in the lower chamber 180 a.

In reference to FIG. 2, in some embodiments of the invention, a netforce can be created due to the area difference between chamber 180 band 180 a that can cause the diaphragm 160 to be pushed down to closethe valve 162. In some embodiments, fluid pressure can be applied on thestem at two generally opposite locations, one near the sealing zone 200and one near the sealing zone 250. Since the diameter of the stem 129 atzone 200 (section 129 b of the stem 129) is equal to diameter at zone250 (section 129 c of the stem 129), the net force on the stem 129 duethe fluid pressure can be substantially equal to zero. The only force onthe stem 129 at this position can be frictional force with the meteringseal 177 (e.g., through contact with one or more of regions 180, 182,and 184 of the metering seal 177) to maintain this stem 129 position.Therefore, the frictional force is the only force required to move thestem from the off position to the on position.

FIG. 4 shows a cross-section of a valve in an open position according toone embodiment of the invention. Further, FIG. 5A depicts an enlargedview of a portion of the valve of FIG. 4 according to some embodimentsof the invention, and FIG. 5B illustrates a partial cross-section of aportion of the metering seal with stem of FIG. 5A shown to provideclarity of the position of the stem 129 in the metering seal 177.

In some embodiments of the invention, the stem 129 can be moved up sothat its sealing zone is away from the sealing zone 200 of the meteringseal 177. In this instance, the flutes (section 129 a) on the stem canallow fluid in the upper chamber 180 b to be bled out to atmospherewhile another sealing zone on the stem is sealed off by the sealing zone225. This can cause the upper chamber 180 b to be depressurized andcause a net force on the diaphragm 160 of valve 162 of the flow controlside 175 a. This can enable the diaphragm 160 of valve 162 to be forcedaway from the sealing surface 164, and enabling fluid flow to take place(show as arrows toward fluid outlet body 115.

In another embodiment of the invention, a valve can include only themetering side 175 b such as shown in partial assembly 101 of FIG. 3Awithout using the flow control side 175 a. In some embodiments, byenlarging the flow paths (such as upper and lower flow channels 150,155), enough flow rate to be generated for the valve to operatesatisfactorily. In some embodiments, both sides (upper and lower flowchannels 150, 155) that feed into this valve embodiment can be connectedto a common inlet of a fluid supply. In this instance, a balanced forceand bistable condition is preserved, and the only force to overcomeduring the activation is frictional force between the stem 129 andmetering seal 177. In some embodiments, in the partial assembly 101 orassembly 100, only low forces are needed to actuate the valve, enablingvalve actuation to be powered by batteries, by solar power, or other lowvoltage and current sources.

It will be appreciated by those skilled in the art that while theinvention has been described above in connection with particularembodiments and examples, the invention is not necessarily so limited,and that numerous other embodiments, examples, uses, modifications anddepartures from the embodiments, examples and uses are intended to beencompassed by the description and figures, as well as in the followingclaims.

1. A valve assembly comprising: at least one metering seal comprising amain channel, the main channel including regions with a first diameterand regions with at least a second diameter, the first diameter beingsmaller than the second diameter; a stem positioned in the at least onemetering seal extending from at least a first end of the at least onemetering seal to a second end of the at least one metering seal, thestem comprising at least one fluted section; and first and second flowchannels extending across at least a partial width of the at least onemetering seal, the first flow channel positioned at or near the firstend of the at least one metering seal, and the second flow channelpositioned at or near the second end of the at least one metering seal.2. The valve assembly of claim 1, wherein the first flow channel extendsto and couples with the main channel.
 3. The valve assembly of claim 1,wherein the second flow channel extends to and couples with the mainchannel.
 4. The valve assembly of claim 1, further comprising a lowerflow channel extending to and coupled to the first flow channel.
 5. Thevalve assembly of claim 1, further comprising an upper flow channelextending to and coupled to the second flow channel.
 6. The valveassembly of claim 4, wherein the lower flow channel extends from atleast one of a fluid supply and an actuable valve, the actuable valveconfigured to at least partially open and close to control passage offluid to the lower flow channel.
 7. The valve assembly of claim 5,wherein the upper flow channel extends from at least one of a fluidsupply and an actuable valve, the actuable valve configured to at leastpartially open and close to control passage of fluid to the upper flowchannel.
 8. The valve assembly of claim 1, wherein at least a portion ofone or more of the non-fluted sections comprises a diameter dimensionedto couple with the at least one metering seal in the main channel inregions that comprise the second diameter.
 9. The valve assembly ofclaim 8, wherein at least a partial seal or fluid-tight seal is formedby the coupling of the one or more of the non-fluted sections couplingwith the at least one metering seal in the main channel in regions thatcomprise the second diameter.
 10. The valve assembly of claim 1, whereinthe stem is positioned in the main channel so that at least a portion ofthe fluted section is coupled with or proximate a region of the mainchannel comprising the second diameter.
 11. The valve assembly of claim1, wherein the stem is positioned in the main channel as an arrangementwith at least a portion of the fluted section being at least one ofcoupled with, proximate to, and fluidly coupled to the second flowchannel, the arrangement configured to enable fluid flow between themain channel and the second flow channel.
 12. The valve assembly ofclaim 1, wherein the stem is positioned in the main channel as anarrangement with at least a portion of the non-fluted section being atleast one of coupled with, and proximate to the second flow channel, thearrangement configured to at least partially prevent fluid flow betweenthe main channel and the second flow channel.
 13. The valve assembly ofclaim 1, wherein the stem is positioned in the main channel as anarrangement with at least a portion of the fluted section being at leastone of coupled with, proximate to, and fluidly coupled to the secondflow channel, the arrangement configured to enable fluid flow out of themain channel adjacent the second end of the at least one metering seal.14. The valve assembly of claim 1, comprising at least one gap betweenthe inner surface of the at least one metering seal and the outersurface of the stem, the gap configured and arranged to enable fluid tocommunicate from a lower chamber of an adjacent valve to an upperchamber of an adjacent valve to bring the pressure in the upper chamberup to the pressure in the lower chamber.
 15. The valve assembly of claim1, wherein the stem comprises a bistable state held in a static positionin the main channel by friction between an internal surface of the mainchannel comprising the first diameter, and/or a fluid force acting ongenerally opposite ends of the stem.
 16. The valve assembly of claim 15,wherein the position of the stem enables a fluid coupling of the firstand second flow channels and the main channel.
 17. An assemblycomprising: a valve assembly comprising a flow control side and ametering side, the flow control side comprising valve separating a lowerchamber and an upper chamber, the valve configured and arranged tocontrol fluid flow between the flow control side and the metering side,and wherein the metering side comprises: at least one metering sealcomprising a main channel, the main channel including regions with afirst diameter and regions with at least a second diameter, the firstdiameter being smaller than the second diameter; a stem positioned inthe at least one metering seal extending from at least a first end ofthe at least one metering seal to a second end of the at least onemetering seal, the stem comprising a fluted section positioned betweentwo non-fluted sections, wherein the diameter of stem in the flutedsection is smaller than the diameter of the stem in the non-flutedsections; and first and second flow channels extending across at least apartial width of the at least one metering seal, the first flow channelpositioned at or near the first end of the at least one metering seal,and the second flow channel positioned at or near the second end of theat least one metering seal.
 18. The assembly of claim 17, furthercomprising a lower flow channel extending to and coupled to the firstflow channel, and an upper flow channel extending to and coupled to thesecond flow channel; and wherein the first and second flow channelsextend to and couple with the main channel.
 19. The assembly of claim17, further comprising a lower flow channel extending between the flowcontrol side and the metering side and coupled to the first flowchannel, and an upper flow channel extending between the flow controlside and the metering side and coupled to the second flow channel. 20.The assembly of claim 17, further comprising at least one gap betweenthe inner surface of the at least one metering seal and the outersurface of the stem, the gap configured and arranged to enable fluid tocommunicate between the lower chamber and the upper chamber via the atleast one metering seal.
 21. A valve stem control method comprising:providing at least one metering seal and stem assembly, the at least onemetering seal and stem assembly comprising a plurality of sealing zones;and providing a balanced fluidic pressure to the at least one meteringseal and stem assembly, the fluidic pressure being substantiallybalanced to substantially cancel a force acting and/or inducing momentumof at least a portion of the stem assembly.
 22. The method of claim 21,wherein the plurality of sealing zones comprises three sealing zones ofthe at least one metering seal.
 23. The method of claim 21, wherein theplurality of sealing zones enables at least one of an on function orposition of a valve and an off function or position of a valve.
 24. Themethod of claim 23, wherein the stem comprises a bistable condition whenexposed to two equal and opposite fluid forces at the on and offfunctions or positions, the bistable condition enabling a digitalselection of the on function or position of a valve and/or the offfunction or position of a valve.
 25. The method of claim 24, wherein foran on function or position, the plurality of sealing zones comprises amiddle zone with two zones at each end, the two zones being exposed toatmospheric pressure, wherein a seal of the middle zone is closed, andan upper seal zone of the two zones is opened to depressurize.
 26. Themethod of claim 24, wherein for an off function or position, the stem ismoved so that a middle zone of the plurality of zones is open and thetwo zones are sealed closed.
 27. A fluid control method comprising;providing a fluted stem positioned in a metering seal, the fluted stempositioned in the metering seal to substantially cancel two equal andopposite fluid forces fluid forces acting on generally opposite ends ofthe metering stem by positioning and dimensioning the stem to form afluidically sealed middle zone enabling a digital selection of the onfunction or position and/or the off function or position of the valve.28. A method of claim 27, wherein the bistable on/off condition isproduced solely as a result of the two equal and opposite fluid forces.